Valve stem repair kit and method

ABSTRACT

A method for repairing damaged valve stem assemblies includes enlarging a bore within a body of a valve stem to form an enlarged bore portion and creating a conical hole in an end of the valve stem body around the enlarged bore portion. Internal threads are created within the enlarged bore portion, and a valve stem repair extension is installed in the enlarged bore portion. The valve stem repair extension has a beveled surface that mates with the conical hole to form a hermetic seal between the valve stem body and the valve stem repair extension. The steps of enlarging the bore and creating the conical hole may both be performed using a countersinking drill bit having a beveled cutting portion.

FIELD OF THE INVENTION

The present invention generally relates to the art area concerned withpneumatic tires and their maintenance. More particularly, the presentinvention relates to apparatus and methods for repairing damaged valvestems.

BACKGROUND OF THE INVENTION

Modern pneumatic tires are constructed of a rubber-containing body andtread, and can include an inner tube or can be tubeless. Tires includingan inner tube can be found on bicycles, motorcycles, and many largevehicles. Tubeless tires are used in many applications, including nearlyall cars and light trucks. For both types of pneumatic tires, a volumeof gas is contained within, and provides support to, the other portionsof the tire. Pneumatic tires almost universally include a device thatallows the tire to be inflated or deflated, thereby providing controlover the volume of gas. Typically, this device is a valve stem thatcontains a valve and provides a point of access that is in fluidcommunication with the volume of gas and allow gas to be added to orremoved from the tire.

Valve caps are used with valve stems and protect the valve componentsfrom dirt, water, and other contaminants. Valve caps constructed ofplain black plastic are common, but other materials have been used,including metal. However, using a metal valve cap on an aluminum valvestem has proven problematic. The aluminum valve stem reacts with themetal of the valve cap, especially in the presence of humidity, leadingto corrosion. It has been observed that when the valve stem and thevalve cover are dissimilar metals, the corrosion process may beaccelerated. Valve stem damage caused by corrosion can be severe, insome cases leading to the valve stem breaking, especially near the areaof the valve stem contacting the valve cap. If a valve stem breaks, itis possible that its air containing functions could be compromised,leading to the rapid deflation of a tire.

Tire pressure monitoring systems (TPMS) have been developed formonitoring the air pressure inside pneumatic tires and can providereal-time pressure information to a driver of a vehicle having such asystem. For many designs of TPMS used with tubeless tires, a pressuresensor is connected to, or is integral with, a section of the valve stemwithin the tire. The combination of a valve stem and a TPMS sensor maybe referred to as a TPMS valve stem assembly. The sensor measures thepressure in the tire and communicates the pressure measurement to areceiver, which in turn relays pressure information to an instrumentperceivable by a driver. TPMS valve stem assemblies are more susceptibleto damage by corrosion than other valve stems that are not associatedwith a TPMS sensor because they are made of aluminum, rather than brass.

Damaged TPMS valve stem assemblies can require especially costlyrepairs. For TPMS valve stem assemblies that have become damaged (suchas by corrosion), the tire must be disassembled and the entire TPMSvalve stem assembly replaced. This is expensive, time-consuming, andinconvenient. Specifically, the tire and wheel assembly must be removedfrom the vehicle and the tire demounted from the wheel. Then, a new TPMSvalve stem assembly is installed and the tire is remounted on the wheeland re-inflated. The tire and wheel assembly is then re-balanced andre-installed on the vehicle. Finally, the new TPMS sensor is programmedto work with the vehicle's system. And because the TPMS sensor isconnected to or integral with the valve stem, the entire TPMS valve stemassembly must be replaced, even though the sensor component may beperfectly functional. Alternatively, a replacement valve stem may beinstalled on a TPMS rather than replacing the entire unit. However,installing a replacement valve stem still requires that the tire beremoved from the wheel and the TPMS unit be removed from the wheel. Oncea new stem has been installed, the TPMS and tire must be reassembled.

Thus, a need exists for improvements in addressing damaged TPMS valvestems and the costs associated with their replacement.

SUMMARY OF THE INVENTION

In general, a valve stem repair extension according to the presentinvention includes a generally cylindrical hollow body; a threadedattachment portion on one end of said body for mating with a threadedbore in a damaged valve stem assembly; an outer threaded portion on anend of said body opposite said threaded attachment portion for matingwith a valve cap; a valve core threaded into an inner threaded portionof said body; and a beveled surface adjacent to said threaded attachmentportion for mating with a conical hole in the threaded bore of thedamaged valve stem assembly to create a hermetic seal between the valvestem repair extension and the valve stem assembly.

In accordance with at least one aspect of the present invention, amethod of repairing damaged valve stems includes the steps of enlarginga bore within a body of a valve stem to form an enlarged bore portion;creating a conical hole in an end of the valve stem body around saidenlarged bore portion; creating internal threads within said enlargedbore portion; and installing a valve stem repair extension in saidenlarged bore portion, said valve stem repair extension having a beveledsurface that mates with said conical hole to form a hermetic sealbetween said valve stem body and said valve stem repair extension.

In accordance with at least one aspect of the present invention, a valvestem repair kit includes a valve stem repair extension having a beveledportion adjacent to a threaded attachment portion; and a countersinkingdrill bit having a beveled cutting surface for forming a conical hole ina damaged valve stem body.

BRIEF DESCRIPTION OF THE DRAWINGS

For a full understanding of the invention reference should be made tothe following detailed description and the accompanying drawings,wherein:

FIG. 1 depicts a valve stem assembly that includes a TPMS sensorinstalled in a wheel and tire assembly.

FIG. 2 depicts the valve stem of FIG. 1 installed in a wheel and tireassembly, but in a damaged state.

FIG. 3 depicts a countersinking drill bit used for repairing a damagedvalve stem.

FIG. 4 depicts the valve stem of FIG. 2 after drilling, countersinking,and tapping steps have been performed to prepare it to receive a valvestem repair extension.

FIG. 5 depicts a valve stem repair extension.

FIG. 6 depicts the valve stem repair extension of FIG. 5 installed intothe valve stem of FIG. 4.

FIG. 6A is an enlarged view of a portion of FIG. 6 showing matingbeveled surfaces of a valve stem repair extension and a body of a valvestem assembly.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring now to FIG. 1, a valve stem assembly is shown and is generallyindicated by the numeral 10. The valve stem assembly 10 is typical ofvalve stem assemblies used with modern pneumatic tires and includes ahollow and cylindrical metal body 12 defining a bore 14 extending alongthe length of the body 12. The features of the valve stem assembly 10are consistent with the features of valve stem assemblies, generally,which have standardized sizes and dimensions.

At an access end 16 of valve stem assembly 10, an externally threaded(male) portion 18 is provided for mating with an associated valve cap(not shown). An internally threaded (female) portion 20 receives a valvecore 22. Valve core 22 is removably threaded into body 12 and generallyincludes a poppet valve assisted by a spring. In the region nearthreaded portions 18 and 20, the material thickness of body 12 is theslightest, making the region more susceptible to being damaged or brokenthan other thicker parts of the valve stem. Access end 16 is where atechnician would connect an air supply hose to valve stem assembly 10 toinflate a pneumatic tire associated with the valve stem. Such uses ofvalve stems are generally known in the art and no further description isnecessary to understand the present invention.

At the other end of valve stem assembly 10 is a TPMS sensor 24. FIG. 1shows valve stem assembly 10 in the context of how it would be situatedin a tubeless tire and wheel assembly. Most of body 12 extends from thewheel 26 and the TPMS sensor 24 is positioned on the inside portion ofthe wheel. In such a position, the TPMS sensor 24 would be inside a tireinstalled on the wheel and access end 16 would be outside the tire andwheel assembly and accessible to a technician.

A mounting nut 30 may be used as part of valve stem assembly 10 to forma tightened connection between the valve stem assembly and an associatedwheel. Mounting nut 30 includes an internal threaded (female) portion 32for mating with an external threaded portion 34 of body 12. Mounting nut30 is useful for the installation of valve stem assembly 10 onto a wheelof a tubeless tire and wheel assembly, with mounting nut 30 beingrotated to tighten the connection between the valve stem and the wheel.Mounting nut 30 can define a hexagonal portion 36 resembling the head ofa bolt to allow for the easy manipulation of the mounting nut with ahand tool, such as a socket wrench. While a mounting nut is not crucialto features of the present invention, they are encountered in the valvestem arts.

Turning to FIG. 2, valve stem assembly 10 is shown in a damaged state.In particular, part of body 12 and valve core 22 have broken off nearaccess end 16, so that only a portion 18 a of the original externallythreaded portion 18 remains on the valve stem assembly 10. Also, thevalve core 22 is broken so that only a portion 22 a remains in the body12. The broken body 12 creates a jagged broken edge 40. Repairing thedamaged valve stem assembly 10 would be preferable to replacing it, andthe apparatus and methods for doing so will now be described.

A countersinking drill bit is used to prepare a damaged valve stem forrepair and is generally indicated by the numeral 50 in FIG. 3.Countersinking drill bit 50 is a twist drill bit and includes a cuttingtip 52, a first fluted portion 54, a beveled cutting portion 56, and asecond fluted portion 58. Cutting tip 52 is useful for drillingcylindrical holes in an object. Beveled cutting portion 56 cuts aconical hole in an object. Fluted portions 54 and 58 serve to move chipsaway from the cutting portions 52 and 56, respectively. The use of drillbits, such as countersinking drill bit 50, and their associated drillswill be appreciated by a skilled technician. The size characteristics ofcountersinking drill bit 50 are chosen to create holes that work with avalve stem repair extension, which will be described more fully below.

Before countersinking drill bit 50 is used on the damaged valve stemassembly 10, the remaining portion 22 a, if any, of the valve core 22must be removed from the valve stem. Valve core tools are useful forinstalling, removing, and maintaining valve cores and are commerciallyavailable. An example of a suitable valve core tool for removing theportion 22 a is the Ken-Tool 30215 4-Way Valve Core Tool, sold by SummitTool Company of Akron, Ohio. All of portion 22 a of valve core 22 mustbe removed from valve stem assembly 10, including any bits of the valvecore body or valve core seal which may have remained in the valve stem.The removed portions will not be re-used and can be discarded. Once thevalve core 22 is completely removed from the valve stem assembly 10, thevalve stem should be empty and the technician should assure that thereis nothing in the bore 14.

Once the valve core 22 has been completely removed, countersinking drillbit 50 is used on the damaged valve stem assembly 10 as follows. Withreference to the features shown FIG. 2, the cutting tip 52 is placedinto the bore 14 of the valve stem assembly 10 near jagged broken edge40 so that the drill bit is essentially concentric with the bore.Countersinking drill bit 50 is activated, providing torque on the drillbit, which begins cutting into the body 12 of valve stem assembly 10.Countersinking drill bit 50 is advanced in bore 14 in a directionparallel with the bore, and the first cutting portion 52 cuts acylindrical hole in body 12, essentially increasing the diameter of thebore to create an enlarged bore portion. Countersinking drill bit 50 isadvanced further, and the second cutting portion 56 completely cuts awaythe body 12 in the area of the outer threaded portion 18 a.Countersinking drill bit 50 is advanced until the outer threaded portion18 is completely removed from the body 12 and the beveled cuttingportion 56 cuts a conical hole in a portion of the body below where theouter threaded portion 18 had previously been. The countersinking drillbit 50 is then withdrawn from the valve stem assembly 10.

The axial length of first cutting portion 54 is chosen so that when thebeveled cutting portion 56 cuts its conical hole, the enlarged boreportion extends sufficiently far into body 12 in order for a valve stemrepair extension to be completely received therein. The valve stemrepair extension will be described, along with its relationship to thevalve stem 10, below.

A tap is then used to create threads in the enlarged bore portion of thebody 12 drilled out by the countersinking drill bit 50. A suitable tapwill create threads corresponding with the threads on a valve stemrepair extension. Taps are generally available in the market andexamples of suitable taps are those having a T-shaped handle, whichprovide a convenient wrenching surface for a technician to use whentapping the threads.

Turning to FIG. 4, a valve stem assembly 10 is shown after it has beendrilled and tapped. It includes an enlarged bore portion 60 in body 12created by the first cutting portion 54 of the countersinking drill bit50 during the drilling step. It also includes a beveled surface 62created by the beveled cutting surface 56 during the drilling step.Beveled surface 62 defines a conical hole 64 in body 12 that leads intothe enlarged bore portion 60. Internal threading (female) 66 is includedin enlarged bore portion 60 and was created during the tapping step.

A valve stem repair extension is shown in FIG. 5 and is generallyindicated by the numeral 80. Valve stem repair extension 80 includes ahollow and generally cylindrical body 82 that defines a bore 84extending along the length of the body. Body 82 includes at one end athreaded attachment portion 86 that is designed to mate with theenlarged bore portion 60 of the valve stem assembly 10. At the otherend, an outer threaded (male) portion 88 is provided for mating with avalve cap (not shown). A valve core 90 is threaded into an innerthreaded (female) portion 92 of body 82. Knurled portions 94 may beprovided to improve the tactile handling of the valve stem repairextension as it is twisted so as to thread into the body of a valve stemassembly. Body 82 can include a cylindrical shank 96 between a knurledportion 94 and the threaded attachment portion 86. Body 82 includes abeveled surface 98 that is designed to fit within the conical hole 64created in the body 12 of the valve stem assembly 10 during the drillingstep, thereby creating a tight and sealed connection between the valvestem repair extension 80 and the valve stem assembly 10.

Valve stem repair extension 80 is installed into the valve stem assembly10 (as shown in FIG. 4, after the drilling and tapping steps) asfollows. Threaded attachment portion 86 is inserted and threaded intothe internal threading 66 of enlarged bore portion 60. Thread sealant(not shown) may optionally be applied to the threaded attachment portion86 before it is threaded into the enlarged bore portion 60 to encouragean improved seal between the two pieces. The valve stem repair extension80 is threaded into the valve stem assembly 10 until the beveled surface98 (of the valve stem repair extension) snugly engages the beveledsurface 62 (of the valve stem assembly). The corresponding shapes of thetwo pieces allow a tight seal to be created when the conical shape ofthe valve stem repair extension is pushed into the conical hole of thevalve stem assembly. Achieving a tight seal is important to prevent airfrom escaping through the repaired valve stem assembly.

A repaired valve stem assembly is shown in FIG. 6. The valve stem repairextension 80 has been threaded into the body 12 of the valve stemassembly 10 to the point where the beveled surfaces 98, 62 contact andmake a tight seal between the two pieces. As shown, the enlarged boreportion 60 extends sufficiently far into body 12 to accommodate thecomplete insertion of the valve stem repair extension 80. Once the valvestem assembly 10 has been thus repaired, bore 14, enlarged bore portion60 (both in the valve stem assembly 10) and bore 94 (in the valve stemrepair extension 80) are all in fluid communication, and the valve stemrepair extension 80 can be used to facilitate the inflation or deflationof an associate tire, with a new access point 100 being created near thevalve core 90.

The steps for repairing a damaged valve stem assembly can be summarizedas follows. First, any remaining portion of a damaged valve core,including the valve core body and valve core seal, is removed from thevalve stem of the valve stem assembly. Once the valve core has beenremoved, a countersinking drill bit is used to enlarge the size of thebore within the valve stem, to remove the broken outer threaded portionof the valve stem, and to create a beveled surface defining a conicalhole in the valve stem body. A tap is then used to create threads in theenlarged bore portion of the body of the valve stem, the threads createdby the tap being adapted to engage and receive a valve stem repairextension. A valve stem repair extension is then installed in theenlarged bore, the valve stem repair extension having a beveled surfaceon one end of its body that mates with the conical hole in the valvestem body to create a hermetic seal. In this way a damaged valve stemassembly can be repaired without the expense and hassle associated withreplacing the assembly.

A kit including components for repairing a damaged TPMS valve stemassembly can be provided and can comprise any or all of the componentsdiscussed above, including: (1) a valve stem repair extension, (2) acore tool for removing the old valve core from the damaged valve stemassembly, (3) a countersinking drill bit for drilling out the damagedvalve stem assembly, (4) a tap for creating threads in the drilled-outvalve stem assembly, and (5) thread sealant.

It is thus evident that apparatus and method for repairing damaged valvesteps constructed and performed as described herein substantiallyimproves the art. In accordance with the Patent Statutes, only the bestmode and preferred embodiment have been presented and described indetail. The invention should not be limited by the drawings or thedescription provided herein. For an appreciation of the true scope andbreadth of the invention, reference should be made only to the followingclaims.

1. A valve stem repair extension comprising: a. a generally cylindricalhollow body; b. a threaded attachment portion on one end of said bodyfor mating with a threaded bore in a damaged valve stem assembly; c. anouter threaded portion on an end of said body opposite said threadedattachment portion for mating with a valve cap; d. a valve core threadedinto an inner threaded portion of said body; and e. a beveled surfaceadjacent to said threaded attachment portion for mating with a conicalhole in the threaded bore of the damaged valve stem assembly to create ahermetic seal between the valve stem repair extension and the valve stemassembly.
 2. The valve stem repair extension of claim 1, furthercomprising a valve cap received on said outer threaded portion of saidbody.
 3. The valve stem repair extension of claim 1, further comprisingknurled portions for improving tactile handling of the valve stem repairextension during installation.
 4. The valve stem repair extension ofclaim 1, further comprising a cylindrical shank positioned between aknurled portion of said body and said threaded attachment portion.
 5. Amethod of repairing damaged valve stems comprising: a. enlarging a borewithin a body of a valve stem to form an enlarged bore portion; b.creating a conical hole in an end of the valve stem body around saidenlarged bore portion; c. creating internal threads within said enlargedbore portion; and d. installing a valve stem repair extension in saidenlarged bore portion, said valve stem repair extension having a beveledsurface that mates with said conical hole to form a hermetic sealbetween said valve stem body and said valve stem repair extension. 6.The method of claim 5, further comprising the step of removing anyremaining portion of a damaged valve core from the valve stem prior toenlarging the bore to form an enlarged bore.
 7. The method of claim 5,wherein the steps of enlarging the bore and creating the conical holeare both performed using a countersinking drill bit having a beveledcutting portion.
 8. The method of claim 5, wherein the steps ofenlarging the bore and creating the conical hole are both performedusing a countersinking drill bit having a first cutting portion forforming the enlarged bore portion, and a second beveled cutting portionfor removing a broken threaded portion of the body of the valve stem,and forming the conical hole.
 9. The method of claim 5, wherein the stepof creating the internal threads is performed using a tap.
 10. Themethod of claim 5, wherein the step of installing a valve stem repairextension includes installing a valve stem repair extension having abody with a bore disposed therein, a threaded attachment portion at oneend of the body adapted to mate with the enlarged bore portion of thevalve stem, and a valve core within the bore.
 11. The method of claim10, further comprising the step of applying a thread sealant to thethreaded attachment portion prior to the step of installing the valvestem repair extension.
 12. A valve stem repair kit comprising: a. avalve stem repair extension having a beveled portion adjacent to athreaded attachment portion; and b. a countersinking drill bit having abeveled cutting surface for forming a conical hole in a damaged valvestem body.
 13. The kit of claim 12, further comprising a valve stem coretool for removing an old broken valve core from a damaged valve stemassembly.
 14. The kit of claim 12, further comprising a tap for creatingthreads in a drilled-out valve stem assembly.
 15. The kit of claim 12,further comprising a thread sealant.
 16. The kit of claim 12, whereinsaid valve stem repair extension includes a generally cylindrical hollowbody; a threaded attachment portion on one end of said body for matingwith a threaded bore in a damaged valve stem assembly; an outer threadedportion on an end of said body opposite said threaded attachment portionfor mating with a valve cap; a valve core threaded into an innerthreaded portion of said body; and a beveled surface adjacent to saidthreaded attachment portion for mating with a conical hole in thethreaded bore of the damaged valve stem assembly to create a hermeticseal between the valve stem repair extension and the valve stemassembly.